This invention relates to roller housing assemblies for the sliding doors of railroad freight cars and more particularly relates to roller housing assemblies for use with railroad freight cars having so-called plug doors.
The present roller assembly manufactured for use by original equipment manufacturers or produced for replacement of worn or broken roller housing assemblies generally comprises a center block of solid metal connecting two hollow wheel or roller wells. The center block of such a roller assembly has a vertical socket or seat and in many cases such a socket is threaded to receive therein an exteriorly threaded bushing to enable the bushing to be screwed up and down. The bushing has a central socket which is adapted to receive the bottom end of one of the support pins of the plug door. By screwing the bushing up and down, the position of the pin and hence the plug door can be adjusted so that it can be closely aligned with the door opening when ready to be closed.
It should be understood that plug doors are those which slide on rails along the sides of the freight car and, when aligned with the respective door openings, are swung on their supports on the roller housings into the door openings and clamped in place. In other words, for movement, a door slides parallel with the freight car sides and for securement, it is translated laterally into or out of engagement with the door opening. This sort of translative movement means that the doors must be mounted on vertical shafts or rods which have crank formations at their bottom ends, these crank formations terminating in short vertical pins or rods that are mounted in the sockets of the roller housing assemblies. There are normally two such assemblies for each door and these ride upon rails that are secured to the freight car parallel with and about at the same level as the bottom sill of the door openings.
Some door assemblies provide for vertical adjustment of the doors by manipulation of the pin linkages or connections so that the center block of the roller assembly is provided with a plain cylindrical socket that receives the bottom end of the pin. The door may be raised or lowered by adjustments which do not use any change of position of the pins in their sockets.
Railroad freight cars take considerable abuse from freight handlers and the machinery that they use for loading and unloading freight. The sockets of roller housings are distorted and bent; the threads of bushings are stripped and jammed and the bushings themselves are smashed. In such cases the normal procedure has been to replace the entire roller housing assembly because either the socket was cut directly into the housing center block or the block was threaded to receive the threaded bushing.
In recent years, a replacement kit was made available for replacement of several different types of assemblies, but that kit required a threaded socket in the housing for pin reception where the door was vertically adjusted by raising and lowering the pin as opposed to a different type of adjustment not changing the depth of the pin in its socket.
According to the invention, a wide range of different types of roller housing assemblies could be replaced by a single housing structure with one of two different types of bushings assembled therein. A plain one is provided for the replacement of the type of housing wherein the pin is not required to be vertically adjustable within the socket itself, and a theaded one is furnished for the type of housing where the pin is required to be vertically adjustable within the socket. In either case, no work is required to be performed on the housing as furnished to the user and he merely chooses the type of bushing to associate with the housing, drops it in place and he is ready to mount it on its rail and connect to the freight car door mechanism. All he need do is to weld shims, brackets or hooks to feet or tabs depending from the furnished housings and/or trim or eliminate some of these tabs in order to adapt the housing to almost any one of many different kinds of door mechanisms in use today.
The invention need not only be used for replacement, but could be adapted readily by original equipment manufacturers for use with their door mechanisms and equipment as installed when the freight car is newly built.
The invention enables a kit to be furnished to the railroad repair shop with both kinds of bushings, leaving it to the shop personnel to choose the one needed. The modifications of the tabs can be undertaken by cutting, welding, etc., and even the shims, brackets, hooks or other small parts may be furnished with the kit. An advantage of the invention is that once the repair shop has purchased a kit and installed a roller housing assembly, it may not be required to replace the same throughout the normal life of the entire door because, any time the bushing gets damaged, only the small part need be replaced.
Attention is invited to prior art which is known to the applicants and which is presented to show the different forms of freight car door assemblies which use the general type of housing of the invention. Such prior art comprises:
Bailey U.S. Pat. No. 4,109,847 PA1 Beauchamp U.S. Pat. No. 3,106,000
and the references cited in each of these patents.